Call function with setInterval in jQuery?

To write the best code, you “should” use the latter approach, with a function reference:

var refreshId = setInterval(function() {}, 5000);

or

function test() {}
var refreshId = setInterval(test, 5000);

but your approach of

function test() {}
var refreshId = setInterval("test()", 5000);

is basically valid, too (as long as test() is global).

Note that there is no such thing really as “in jQuery”. You’re still writing the Javascript language; you’re just using some pre-made functions that are the jQuery library.